package cn.have.lb;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @ClassName MyLB
 * @Author 王新
 * @Date: 2022/1/24 13:01 星期一
 * @Version 1.0
 * @Description 手写本地负载均衡器
 */
@Component
public class MyLB implements LoadBalancer{

    private AtomicInteger atomicInteger =new AtomicInteger(0);

    public final int getAndIncrement() {
        int current;
        int next;
        do {
            current = this.atomicInteger.get();
            next = current >= 2147483647 ? 0 : current + 1;

        }while (!this.atomicInteger.compareAndSet(current, next));
        System.out.println("*****next: "+next);
        return next;
    }

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);
    }
}
